A machine (e.g., a wheel loader, an excavator, a front shovel, a bulldozer, a backhoe, a telehandler, etc.) may be used to move heavy loads, such as earth, construction material, and/or debris. The machine may utilize an implement to move the loads. The implement may be powered by a hydraulic system that may use pressurized fluid to actuate a hydraulic actuator to move the implement.
During operation of the machine, the implement may be raised to an elevated position. As the implement may be relatively heavy, the implement may gain potential energy when raised to the elevated position. As the implement is released from the elevated position, this potential energy may be converted to heat when pressurized hydraulic fluid is forced out of the hydraulic actuator and is throttled across a valve and returned to a tank. The conversion of potential energy into heat may result in an undesired heating of the discharged hydraulic fluid, which may require that the machine possess additional cooling capacity. Recovering that lost or wasted potential energy for reuse may improve machine efficiency.
One system designed to recycle the energy associated with lowering a load is disclosed in U.S. Pat. No. 6,584,769 to Bruun (“Bruun”). Bruun discloses a hydraulic circuit that includes a variable hydraulic machine, a servo pump, and an accumulator. During operation, pressurized oil in the accumulator flows through a bi-directional pump of the variable hydraulic machine, which then conveys the oil to a lifting cylinder. In the event of a lowering movement, the direction of flow in the bi-directional pump is changed and oil is supplied to the accumulator. However, the hydraulic circuit in Bruun may not efficiently recover or reuse potential energy from the lowered load, and the system may be relatively complex and costly.
The system of the present disclosure is directed toward solving one or more of the problems set forth above and/or other problems of the prior art.